Method for producing basic metal nitrate

ABSTRACT

A process in which a basic metal nitrate is obtained in a high yield is provided. 
     A process for producing a basic metal nitrate, which comprises adding an aqueous solution of a metal nitrate or an aqueous solution of a mixture of a metal nitrate and a water-soluble additive and an alkali solution to a reaction vessel in which a reaction solvent whose pH at 20° C. is adjusted to 6 or less is present, and conducting the reaction with stirring.

This application is the national phase under 35 U.S.C. 371 of PCTInternational Application No. PCT/JPO2/03005 which has an Internationalfiling date of Mar. 27, 2002, which designated the United States ofAmerica.

TECHNICAL FIELD TO WHICH THE INVENTION BELONGS

The present invention relates to a process for producing a basic metalnitrate.

PRIOR ART

With respect to a process for producing a basic metal nitrate, variousprocesses have been so far known. For example, as a process forproducing a basic copper nitrate using a copper nitrate solution, aprocess described in GMELINS HANDBUCH DERANORGANISCHEN CHEMIE “KUPFER”Teil B, pp. 188-193 (System Number 60), 1958; VERLAG CHEMIE, GMBH.,WEINHEIM/BERGSTRASSE is known. In this literature, a process using acopper nitrate solution and ammonia or an alkali hydroxide, a reactionof a dilute copper nitrate aqueous solution with a 0.1 N sodiumhydroxide aqueous solution, a reaction of a neutral copper nitratesolution with a sodium hydroxide aqueous solution, a reaction withammonium nitrate in the presence of air and water and the like aredescribed as a process for producing a basic copper nitrate. However, inall of these processes, a yield of a basic copper nitrate is unclear,and further a color and a crystalline state of the resulting basiccopper nitrate are not fixed. Thus, it is difficult to utilize the sameindustrially.

Acta Chemica Scandinavia A 30 No. 5 343-350 (1976) describes a processwith a copper nitrate solution—ammonium nitrate solution—aqueous ammoniasystem. However, although the production is conducted using a 4-literflask in this process, an amount is as small as 5 g. When this iscalculated on a plant scale, the yield is as low as approximately 53%.Thus, it is difficult to utilize the same industrially.

In Aust. J. Chem., 1990, 43, 749-754, it is described that when a 10⁻¹ Mpotassium hydroxide solution is gradually added to a solution in which aconcentration of a divalent copper ion in a copper nitrate solution is10⁻⁴ or 10⁻³ M and a concentration of a nitrate anion by potassiumnitrate is 10⁻³, 10⁻² or 10⁻¹ M, a pH value at the initial stage of thesolution is adjusted to approximately 3. This process is, however,problematic in that since it includes a step of using a dilute solution,a production time is more than approximately 36 hours and too long.

DISCLOSURE OF THE INVENTION

The object of the invention is to provide a process for producing abasic metal nitrate in which a high-quality basic metal nitrate isobtained in a high yield and at good efficiency, and to provide a basicmetal nitrate which is composed in accordance with the above process.

The invention provides, as a means for solving the problem, a processfor producing a basic metal nitrate, which comprises adding an aqueoussolution of a metal nitrate or an aqueous solution of a mixture of ametal nitrate and a water-soluble additive and an aqueous solution of analkali to a reaction vessel in which a reaction solvent whose pH (20°C.) before starting a reaction is adjusted to between 1.5 and 2.5 ispresent, and conducting the reaction with stirring through a stirringunit so that the maximum pH value reaches 5.0 to 6.5 during thereaction.

The pH is determined depending on various factors to be described below,and is adjusted by properly selecting the respective factors.

The basic metal nitrate obtained by the process of the inventionincludes compounds represented by the following general formula (I), andsome compounds contain hydrates too.M(NO₃)_(y)·nM(OH)_(z) or M_(x′)(NO₃)_(y′)(OH)_(z′)  (I)[wherein M represents a metal, x′ represents the number of metals, y andy′ each represent the number of NO₃ ions, z′ represents the number of OHions, and n represents a ratio of an M(OH)_(z) moiety to an M(NO₃)_(y)moiety.]

Examples of the compounds corresponding to the general formula (I)include those containing, as a metal M, copper, cobalt, zinc, manganese,iron, molybdenum, bismuth and cerium, such as basic copper nitrates[Cu₂(NO₃)(OH)₃ and Cu₃(NO₃) (OH)₅.2H₂O], basic cobalt nitrate[CO₂(NO₃)(OH)₃], basic zinc nitrate [Zn₂ (NO₃)(OH)₃], basic manganesenitrate [Mn(NO₃)(OH)₂], basic iron nitrate [Fe₄(NO₃)(OH)₁₁.2H₂O], basicmolybdenum nitrate, basic bismuth nitrate [Bi(NO₃)(OH)₂] and basiccerium nitrate [Ce(NO₃)₃ (OH).3H₂O]. Of these, basic copper nitrates(BCN) are preferable.

According to the process of the invention, a basic metal nitrate such asa basic copper nitrate or the like can industrially be produced using astarting material which is less costly and can be procured industriallyeasily without the special need of a special reaction equipment andunder readily controllable reaction conditions. Further, a basic metalnitrate in fixed crystal form having a uniform particle diameter (narrowparticle size distribution) can be obtained in a high yield.

Moreover, when the basic metal nitrate obtained by the process of theinvention is used as an oxidizing agent of a gas generating agent for aninflator, a burning rate of the gas generating agent can be adjusted toa preferable range.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a conceptual view for describing a process of the invention.

FIG. 2 is a graph showing a change in pH of a reaction system with time.

MODE FOR CARRYING OUT THE INVENTION

One embodiment of the process of the invention is described belowaccording to production steps. However, the following production stepscan undergo changes and additions, as required, by modifications whichare commonly conducted by those skilled in the art.

First, an aqueous solution of a metal nitrate or an aqueous solution ofa mixture of a metal nitrate and a water-soluble additive which is areaction starting material and an aqueous solution of an alkali areprepared.

The metal nitrate is preferably a metal salt of at least one metalselected from cobalt, copper, zinc, manganese, iron, molybdenum, bismuthand cerium. Copper nitrate is more preferable.

The water-soluble additive is at least one selected from ammoniumnitrate, ammonium nitrite, ammonium acetate, ammonium carbonate,ammonium bicarbonate, ammonium sulfate, ammonium sulfite, ammoniumbisulfate, ammonium bisulfite, ammonium hydrogensulfate, ammoniumhydrogensulfite, ammonium borate 8-hydrate, ammonium tetraborate,diammonium phosphate, monoammonium phosphate, triammonium phosphate3-hydrate, ammonium sodium hydrogenphosphate 4-hydrate, ammoniumperchlorate, ammonium perrhenate, ammonium cerium (IV) nitrate, ammoniumcerium (III) nitrate 4-hydrate, cerium ammonium (IV) sulfate 2-hydrate,ammonium chromium (III) sulfate 12-hydrate, ammonium cobalt (II) sulfate6-hydrate, ammonium iron (II) sulfate 6-hydrate, ammonium iron (III)sulfate 12-hydrate, ammonium chromate, ammonium dichromate, ammoniummolybdate 4-hydrate, ammoniumvanadate (V), ammonium phosphomolybdate3-hydrate, ammonium phosphotungstate 3-hydrate, manganese (II) ammoniumsulfate, nickel (II) ammonium sulfate 6-hydrate, nickel (II) ammoniumsulfate 6-hydrate, ammonium chloride, ammonium bromide, ammonium iodide,ammonium acetate, ammonium adipate, ammonium alginate, ammoniumbenzoate, ammonium dicitrate, triammonium citrate, ammonium iron (III)citrate, ammonium formate, ammonium tartrate, ammonium hydrogentartrate,ammonium lactate, ammonium methacrylsulfonate, ammonium phthalate,ammonium salicylate, ammonium succinate and ammonium sulfamate. Ofthese, ammonium nitrate is preferable.

The concentration of the metal nitrate in the aqueous solution or theaqueous solution of the mixture is preferably 65% by weight or less,more preferably 40 to 55% by weight. When the concentration of the metalnitrate is too high, crystals of the metal nitrate are precipitated tomake difficult the procedure of charging into a reaction vessel and toincrease the pH of the reaction system. Thus, it is undesirable.

The concentration of the water-soluble additive is preferably 5% byweight or less, more preferably 0.01 to 1.5% by weight. When theconcentration of the water-soluble additive is too high, excess ammoniumion is coordinated in a metallic ion of a metal nitrate, and isstabilized as a complex ion, interrupting the production of a basicmetal nitrate. Thus, it is undesirable.

As the alkali, alkali metal salt hydroxides such as sodium hydroxide,potassium hydroxide, lithium hydroxide and the like are preferable, andsodium hydroxide is more preferable.

The alkali concentration in the aqueous solution of an alkali ispreferably 60% by weight or less, more preferably 20 to 50% by weight.When the alkali concentration is too high, crystals of the alkali areprecipitated to make difficult the procedure of charging into a reactionvessel and to increase the pH of the reaction system. Thus, it isundesirable.

With respect to the mixing ratio of the metal nitrate and the alkali,the alkali is preferably 2 mols or less, more preferably in the range of1.0 to 1.7 mols per one mol of the metal nitrate. When the alkali isless than this range, the quality of the basic metal nitrate is notimproved, and the yield is decreased. Thus, it is meaningless as anindustrial process. Further, when it is more than this range, the metalhydroxide is incorporated into the basic metal nitrate. It is thereforeundesirable.

Subsequently, the aqueous solution of a metal nitrate or the aqueoussolution of the mixture of the metal nitrate and the water-solubleadditive and the alkali solution are added to a reaction vessel in whichthe reaction solvent is present, and the mixture is reacted withstirring through a stirring unit.

A ratio S₁/S₂ of an addition rate S₁ (mol/min) of the metal nitrate toan addition rate S₂ (mol/min) of the alkali is preferably 0.2 to 3.0,more preferably 0.4 to 0.9. When this ratio S₁/S₂ is too low, the pH isabruptly increased in the reaction, and a gel-like metal hydroxide isformed, making it difficult to continue the stirring. Thus, it isundesirable. When this ratio S₁/S₂ is too high, the reaction systemcannot be rendered uniform. Thus, it is undesirable.

The pH at 20° C. of the reaction solvent before starting the reaction is1.5 to 2.5, preferably 1.8 to 2.2. When the pH before starting thereaction is too high, the pH is abruptly increased in the reaction, anda gel-like metal hydroxide is formed, making it difficult to continuethe stirring. Thus, it is undesirable. When the pH in the start-up ofthe reaction is too low, the pH of the reaction system is notsatisfactorily increased during the reaction, and the resulting basicmetal nitrate becomes a non-uniform agglomerate. Thus, it isundesirable.

The reaction solvent is preferably an acid aqueous solution or anaqueous solution of a mixture of an acid and a water-soluble additive. Anitric acid aqueous solution or an aqueous solution of a mixture ofnitric acid and ammonium nitrate is more preferable. At this time, theconcentration of the water-soluble additive is preferably 5% by weightor less, more preferably 0.1 to 3% by weight. When the concentration ofthe water-soluble additive is too high, excess ammonia generated in thereaction solution is coordinated in a metallic ion, and is stabilized asa complex ion as such to increase the pH. Accordingly, a basic metalnitrate is not obtained.

The stirring unit used in the stirring is preferably one having stirringblades which are mounted separately at plural stages in the lengthwisedirection in view of the uniform stirring of the reaction system.

The aqueous solution of a metal nitrate or the aqueous solution of themixture of the metal nitrate and the water-soluble additive and thealkali solution are added to the reaction vessel with stirring throughthe stirring unit. A position where these are added is preferably closerto or next to the stirring blades in the solution, especially preferablyin the vicinity of or next to the stirring blade at the lower stage inthe solution in order that the stirring of the reaction solution isconducted more uniformly in using the stirring blades as the stirringunit.

The reaction is conducted so that the maximum pH value reaches 5.0 to6.5. The maximum pH value is preferably 5.5 to 6.2.

The reaction temperature is preferably 60° C. or less, more preferably10 to 50° C. When the temperature is too high, the basic metal nitrateformed causes a dehydrocondensation reaction with heat, and is convertedinto a metal hydroxide. Thus, it is undesirable.

The stirring rate in the reaction is preferably less than 200 rpm, morepreferably 10 to 150 rpm, further preferably 90 to 110 rpm. When thestirring rate is too high, the maximum pH value in the reaction becomestoo high, and the resulting basic metal nitrate is a sphericalagglomerate having a broad particle size distribution. Thus, it isundesirable.

The reaction time is preferably 20 to 100 hours, more preferably 10 to40 hours.

The basic metal nitrate obtained by the invention can be used as anoxidizing agent of a gas generating agent. In this case, a burning rateof the gas generating agent can easily be adjusted as compared with theuse of other oxidizing agents. Further, the gas generating agent can beused in, for example, an inflator for an air bag of a driver side, aninflator for an air bag of a passenger side, an inflator for a side airbag, an inflator for an inflatable curtain, an inflator for a kneebolster, an inflator for an inflatable seat belt, an inflator for atubular system and a gas generator for a pretensioner in variousvehicles.

EXAMPLES

The invention is illustrated more specifically below by referring toExamples. However, the invention is not limited thereto. The testmethods in the following Examples are described below.

(1) Identification of a Particle Diameter and a Particle Form

A sample powder was fixed on an exclusive sample base. A particlediameter of the sample powder in visual images for observation of x500,x2,000 and x10,000 was measured using a scanning electron microscope,and a particle form was estimated at the same time. Incidentally, whenparticles were particles in the form of needles, a length was defined asa particle diameter. When particles were particles in the form of rods(prisms) or plates, a maximum diagonal length was defined as a particlediameter. Further, when particles were particles in the form of shapessimilar to spheres, a major axis was defined as a particle diameter.

(2) Burning Rate (mm/sec)

15 parts by weight of deionized water was added to a total of 100 partsby weight, namely, 52 parts by weight of a basic copper nitrate, 45parts by weight of nitroguanidine and 3 parts by weight of guar gum, andthese were fully mixed. The mixture was then molded into a cylinderhaving a diameter of approximately 9.6 mm and a height of approximately12.7 mm. This molded product was dried at 80° C. for 16 hours, and thecylindrical molded product was burned from its end surface in a nitrogenatmosphere under a gauge pressure of 70 kg/cm². The rate at this timewas read out from the change in pressure with time, and defined as aburning rate.

Example 1

As shown in FIG. 1, a basic copper nitrate was produced using a 5-literreaction vessel fitted with a stirring unit comprising a total of 5stages of cross blades (the length of the cross blade at the fourthstage from the top is approximately 1.5 times that of the other crossblades which are of the same length). Incidentally, 1 liter of a 0.5% byweight of ammonium nitrate aqueous solution whose pH at 20° C. had beenadjusted to 2.23 with nitric acid was charged into the reaction vesselas a reaction solvent.

First, while the reaction solvent was stirred at 95 rpm by actuating thestirring blades, 6,000 parts by weight of copper nitrate 3-hydrate and66 parts by weight of ammonium nitrate were added to 2,800 parts byweight of deionized water so that copper nitrate 3-hydrate reached 18%by weight calculated as copper and ammonium nitrate 0.75% by weightrespectively. While the mixed aqueous solution (the concentration ofcopper nitrate in the aqueous solution was 53% by weight) was added tothe reaction vessel at a rate of 2.6 ml/min, a 30% by weight of sodiumhydroxide aqueous solution was added to the reaction vessel at a rate of1.8 ml/min at the same time. At this time, the mixture and the aqueoussolution of an alkali were added to a position near the stirring bladeat the fourth stage as shown.

The reaction was conducted under conditions that the stirring rate was95 rpm and the reaction temperature was 40° C. Approximately 21 hourslater, the reaction was terminated. The resulting precipitate wasfiltered at room temperature, and washed with distilled water. Theproduct was dried under normal pressure at 80° C. for 16 hours to obtaina basic copper nitrate. The resulting basic copper nitrate was weaklyagglomerated, primary particles were in the form of bluish green rods(prisms), and a primary particle diameter was 0.5 to 3 μm. The yieldbased on the charged starting material was 96%.

By the way, the maximum pH value of the reaction system at the initialstage of the reaction was 5.72. As the reaction proceeded, the pH wasdecreased, and reached 3.85 after approximately 2 hours. The change inpH of the reaction system with time from 0 to 120 minutes is shown inFIG. 2.

Example 2

A basic copper nitrate was produced in the same manner as in Example 1,provided the pH of the reaction solvent before starting the reaction was1.97 and the reaction time was approximately 24 hours. The resultingbasic copper nitrate was weakly agglomerated, primary particles were inthe form of bluish green rods (prisms), and a primary particle diameterwas 0.5 to 3 μm. The yield based on the charged starting material was99%. By the way, the maximum pH value of the reaction system at theinitial stage of the reaction was 5.90. As the reaction proceeded, thepH was decreased, and reached 3.72 after approximately 2 hours. Thechange in pH of the reaction system with time from 0 to 120 minutes isshown in FIG. 2.

Example 3

A basic copper nitrate was produced in the same manner as in Example 1,provided the pH of the reaction solvent before starting the reaction was2.05 and the reaction time was approximately 24 hours. The resultingbasic copper nitrate was weakly agglomerated, primary particles were inthe form of bluish green rods (prisms), and a primary particle diameterwas 0.5 to 3 μm. The yield based on the charged starting material was100%.

By the way, the maximum pH value of the reaction system at the initialstage of the reaction was 5.72. As the reaction proceeded, the pH wasdecreased, and reached 3.85 after approximately 2 hours. The change inpH of the reaction system with time from 0 to 120 minutes is shown inFIG. 2.

Example 4

A basic copper nitrate was produced in the same manner as in Example 1,provided the pH of the reaction solvent (before starting the reaction)was 2.04 and the reaction time was approximately 27 hours. The resultingbasic copper nitrate was weakly agglomerated, primary particles were inthe form of bluish green rods (prisms), and a primary particle diameterwas 0.5 to 3 μm. The yield based on the charged starting material was99%. By the way, the maximum pH value of the reaction system at theinitial stage of the reaction was 5.84. As the reaction proceeded, thepH was decreased, and reached 3.63 after approximately 2 hours.

Example 5

A basic copper nitrate was produced in the same manner as in Example 1,provided the pH of the reaction solvent before starting the reaction was1.84, the addition rate of the aqueous solution of the mixture of coppernitrate and ammonium nitrate and the addition rate of 30% by weightsodium hydroxide which were the same as in Example 1 were both 1.7ml/min, the stirring rate was 97 rpm and the reaction time was 11 hours.The resulting basic copper nitrate was not agglomerated, particles werein the form of bluish green rods (prisms), and a particle diameter was1.0 to 3.0 μm. The yield based on the charged starting material was 98%.

By the way, the maximum pH value of the reaction system at the initialstage of the reaction was 5.74. As the reaction proceeded, the pH wasdecreased, and reached 3.76 after approximately 2 hours.

Example 6

The production was conducted in the same manner as in Example 1 exceptthat the reaction temperature was 20° C. and the pH before starting thereaction was 1.96 to obtain a basic copper nitrate. The resulting basiccopper nitrate was weakly agglomerated, primary particles were in theform of bluish green rods (prisms) and partially in the form of plates,and a primary particle diameter was 0.5 to 2.0 μm. The yield based onthe charged starting material was 95%.

By the way, the maximum pH value of the reaction system at the initialstage of the reaction was 6.04. As the reaction proceeded, the pH wasdecreased, and reached 4.47 after approximately 2 hours.

Example 7

The production was conducted in the same manner as in Example 1 exceptthat ammonium nitrate was not added to the aqueous solution of coppernitrate and the reaction solvent and the pH before starting the reactionwas 1.88 to obtain a basic copper nitrate. The resulting basic coppernitrate was not agglomerated, and was in the form of bluish green rods(prisms), and a particle diameter was 1.0 to 3.0 μm. The yield based onthe charged starting material was 86%.

By the way, the maximum pH value of the reaction system at the initialstage of the reaction was 5.91. As the reaction proceeded, the pH wasdecreased, and reached 3.45 after approximately 2 hours.

Comparative Example 1

The production was conducted in the same manner as in Example 1 exceptthat the pH of the reaction solvent before starting the reaction was2.04 and the stirring rate in the reaction was 200 rpm. The maximum pHvalue of the reaction system at the initial stage of the reaction was6.90. As the reaction proceeded, the pH value was decreased, and reached3.90 after approximately 2 hours. The resulting basic copper nitrate wasa bluish green spherical agglomerate of 5 to 30 μm in which fine platecrystals having a diameter of 0.5 to 5.0 μm were agglomerated. The yieldbased on the charged starting material was 97%.

Comparative Example 2

The production was conducted in the same manner as in Example 1 exceptthat the pH of the reaction solvent before starting the reaction was0.05, the stirring rate was 100 rpm and the reaction time was 20 hours.The maximum pH value of the reaction system at the initial stage of thereaction was only 4.06. As the reaction proceeded, the pH was decreased,and reached 3.79 after approximately 2 hours. The resulting basic coppernitrate was a non-uniform agglomerate of bluish green plate crystals,and the diameter of the plate crystals was 0.1 to 1.0 μm. The yieldbased on the charged starting material was 99%.

Comparative Example 3

The production was conducted in the same manner as in Example 1 exceptthat the concentration of the copper nitrate aqueous solution was 70% byweight. However, since the copper nitrate crystals in the copper nitrateaqueous solution were precipitated, it could not quantitatively becharged into the reaction vessel, and the pH was increased to exceed 8.Thus, no desired basic copper nitrate was obtained.

Comparative Example 4

The production was conducted under the same conditions as in Example 1except that the concentration of ammonium nitrate in the reactionsolvent was 50% by weight. However, since excess ammonia generated inthe reaction solution was coordinated in a copper ion and stabilized asa complex ion as such in a bluish green solution, the pH was increasedto exceed 11. Consequently, a desired basic copper nitrate was littleobtained.

Comparative Example 5

The production was conducted in the same manner as in Example 1 exceptthat the concentration of sodium hydroxide was 70% by weight. However,since crystals of sodium hydroxide were precipitated, it could notquantitatively be charged into the reaction vessel, the PH was increasednot to exceed 5 and no desired basic copper nitrate was obtained.

Comparative Example 6

The production was conducted in the same manner as in Example 1 exceptthat the addition rate of the mixed solution was 0.1 ml/min and theaddition rate of the sodium hydroxide aqueous solution was 1.8 ml/min.However, the pH was abruptly increased to 11 or more and was notdecreased, and a large amount of gel-like copper hydroxide wasprecipitated which made it impossible to continue the stirring. Thus,the production was interrupted.

Comparative Example 7

The production was conducted in the same manner as in Example 1 exceptthat nitric acid was not added to the reaction solvent in the reactionvessel and the pH at 20° C. was 5.6. However, the pH was abruptlyincreased to 8 or more and was not decreased, and a large amount ofgel-like copper hydroxide was precipitated which made it impossible tocontinue the stirring. Thus, the production was interrupted.

TABLE 1 Primary particle Burning diameter Color of rate (μm)Agglomeration Form crystals (mm/sec) Ex. 1 0.5-3.0 weak agglomerationprisms bluish 10.2 green Ex. 2 0.5-3.0 weak agglomeration prisms bluish10.6 green Ex. 3 0.5-3.0 weak agglomeration prisms bluish 10.4 green Ex.4 0.5-3.0 weak agglomeration prisms bluish 10.1 green Ex. 5 1.0-3.0 noagglomeration prisms bluish 9.1 green Ex. 6 0.5-2.0 weak agglomerationprisms bluish 10.1 green Ex. 7 1.0-3.0 no agglomeration prisms bluish10.0 green Comp. 0.5-5.0 spherical — bluish 8.0 Ex. 1 agglomerate greenComp. 0.1-1.0 non-uniform — bluish 5.5 Ex. 2 agglomerate green

As is apparent from Table 1, the basic copper nitrates obtained inExamples 1 to 7 have the particle diameters and the particle sizedistributions in the appropriate ranges. When these are used as anoxidizing agent, the burning rates of the gas generating agents can beadjusted to the preferable ranges.

1. A process for producing a basic copper nitrate, which comprisesadding an aqueous solution of copper nitrate or an aqueous solution of amixture of copper nitrate and ammonium nitrate and an aqueous solutionof sodium hydroxide to a reaction vessel in which a reaction solvent,whose pH at 20° C before starting the reaction is adjusted to between1.5 and 2.5, is present, and conducting the reaction with stirringthrough a stirring unit so that the maximum pH value reaches 5.0 to 6.5during the reaction.
 2. The process for producing the basic coppernitrate according to claim 1, in which the concentration of the coppernitrate in the aqueous solution of copper nitrate or the aqueoussolution of the mixture of copper nitrate and ammonium nitrate is 65% byweight or less.
 3. The process for producing the basic copper nitrateaccording to claim 1, in which the concentration of ammonium nitrate inthe aqueous solution of the mixture of copper nitrate and ammoniumnitrate is 5% by weight or less.
 4. The process for producing the basiccopper nitrate according to claim 1, in which the concentration of thesodium hydroxide solution is 60% by weight or less.
 5. The process forproducing the basic copper nitrate according to claim 1, in which thereaction solvent is an acid aqueous solution or an aqueous solution of amixture of an acid and a water-soluble additive.
 6. The process forproducing the basic copper nitrate according to claim 5, in which theacid is nitric acid.
 7. The process for producing the basic coppernitrate according to claim 5, in which the concentration of thewater-soluble additive in the reaction solvent is 5% by weight or less.8. The process for producing the basic copper nitrate according to claim1, in which a ratio S_(1/)S₂ of an addition rate Si (mo 1 /min) of thecopper nitrate to an addition rate S₂ (mol/min) of the sodium hydroxidealkali is 0.2 to 3.0.
 9. The process for producing the basic coppernitrate according to claim 1, in which the reaction temperature is 60° Cor less.
 10. The process for producing the basic copper nitrateaccording to claim 1, in which the stirring rate with the stirring unitin the reaction is less than 200 rpm.
 11. The process for producing thebasic copper nitrate according to claim 1, in which a position where theaqueous solution of copper nitrate or the aqueous solution of themixture of copper nitrate and ammonium hydroxide and the sodiumhydroxide solution is added is in the vicinity of or next to thestirring unit in the solution.
 12. A basic copper nitrate having theform of prism which is produced in accordance with the process whichcomprises adding an aqueous solution of a copper nitrate or an aqueoussolution of a mixture of a copper nitrate and a water-soluble additiveand an aqueous solution of an alkali to a reaction vessel in which areaction solvent is present, wherein the pH at 20° C of the reactionsolvent before starting the reaction is adjusted to between 1.5 and 2.5,and conducting the reaction with stirring through a stirring unit sothat the maximum pH value reaches 5.0 to 6.5 during the reaction,thereby precipitating a basic copper metal nitrate particulate producthaving the form of prisms.